What does the moon have to do with Easter?

We all know that the moon affects the tides – but what about Easter? What’s a full moon got to do with when we dig into chocolate eggs?

Read on to discover why this celestial object is a major player in determining when Easter takes place – and how the events of Jesus' life are connected to the skies.

What determines when Easter is?

A key holiday in the Christian calendar, Easter commemorates the death and mysterious rising of Jesus, a Jewish teacher whose life is documented in ancient biblical texts.

But why does Easter fall when it does? Why is it always moving? And why can’t Easter be standardised?

You might not expect it, but it’s all to do with the moon.

How does the moon affect when Easter is?

For those who use the Gregorian calendar, Easter always falls somewhere between 22 March and 25 April each year. And that’s because it’s celebrated on the first Sunday after the first full moon of the vernal equinox – an event fixed at 21 March.

This is known as the Paschal full moon, marking a link between when the Jewish festival of Pasach (Passover) and the Christian festival of Easter are celebrated – we’ll get to that in a moment ...

Hang on: What’s the night sky got to do with Jesus’ life?

There seems to be a link between the events around Jesus’ life and the night sky, right?

At Christmas, the Bible tells us about a group of stargazers, who follow a sign in the sky that leads them to an infant Jesus, raising questions about this mysterious Christmas star.

At Easter, billions of people mark his death in a movable festival that’s set according to the phases of the moon.

So, what exactly is going on here? Why does there seem to be a connection between the life and death of Jesus, and what’s happening up there?

Throughout history, humanity has turned to the night sky as a tool for understanding, using celestial objects as a compass, seeking meaning in the stars, and marking time by the phases of the moon.

Before we had clocks, we had the moon. And before the solar Gregorian calendar was introduced (which we now use in the UK – though it isn’t the standard everywhere), calendars were set by the phases of the moon.

Celestial objects have shaped spiritual beliefs and inspired religious festivals – including when they’re held – for as long as we can remember. We see this mirrored across major world religions, including Judaism and Christianity.

And the time of year when these celebrations are held – and how they’re both set by the moon – isn't the only thing that links the Jewish Pasach festival with the Christian holiday of Easter ...

What is Passover and what does it have to do with Easter?

Passover is one of the oldest continuously celebrated holidays in the Jewish calendar. As Jesus was born into a Jewish family, he would have been accustomed to annual celebrations, which marked the Israelite escape from Egyptian enslavement roughly 3000 years ago – covered in Exodus 12.

Starting with a special family meal known as the seder, it remains one of the most significant festivals in the Jewish calendar.

According to ancient writings on the life of Jesus, he shared a Jewish Pasach (Passover) meal with his friends shortly before his arrest, execution and rumoured resurrection.

Today, this meal is remembered as ‘the Last Supper’ – yep, the inspiration behind Leonardo da Vinci’s masterpiece – and it’s marked on what’s known as Maundy Thursday in our calendar.

OK, so when has Easter been celebrated over the years?

From the beginning, Passover – and the moon that influences when it’s celebrated – has influenced when Easter is celebrated.

Some early Christians, particularly those from Eastern traditions, commemorated Jesus’ death on the same day as the Passover, and his resurrection two days later. Western Christian traditions, on the other hand, celebrated Jesus’ resurrection on the first day of the week: a Sunday, which continues to be an important day of the week for Christians.

When did we start celebrating Easter at this time?

In 325 BCE, a Church gathering – called the Council of Nicaea – aimed to settle the debate over when Easter should be celebrated. It concluded that the Church would mark Easter on the Sunday after the first full moon of the spring equinox.

Today, Protestants and Catholics celebrate Easter between 22 March and 25 April based on the above, although other church traditions celebrate it on different dates. For example, the Eastern Orthodox Church follows the lunar Julian calendar, which means that Easter can be on a different day from when it would fall in the Gregorian calendar.

Why isn't Easter standardised?

Let's be honest: it can be tricky remembering when Easter is in any given year. So why isn’t the date standardised, like most holidays in our calendars?

Perhaps you think we could just choose to mark the events around Jesus’ death at a specific point in spring – like setting the first Sunday of April as Easter Sunday, for example. Given that this is a story about rebirth, that would fit with traditions and the hope of a new season, right?

Well, it’s a fair suggestion. But there’s a reason why Christians continue to commemorate the events surrounding Jesus’ death on different days each year – even over 2,000 years after they’re said to have happened.

Biblical accounts link Jesus’ death to Passover. By aligning the date of Easter with Passover, Jesus’ death takes on an underlying meaning apparent in biblical writings. You can explore this idea further with Easter Reborn: From the Rites of Spring to the Rising of Jesus.